package A.q.day07;
//先思考这一步是不是独立业务-是就生成方法
import java.util.Random;
/**
 * 需求：生成？位验证码（包括大写字母、小写字母、数字）
 */
public class VerificationCode {
    public static void main(String[] args) {
        String code = generateVeriCode(4);//1 做个架子
        System.out.println("验证码:" + code);//1
    }

    /**
     * 生成验证码
     */
    public static String generateVeriCode(int length) {
        String code = "";
        char[] chs = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k',
                'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
                'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G',
                'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R',
                'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '0', '1', '2',
                '3', '4', '5', '6', '7', '8', '9'};
        Random random = new Random();
        for (int i = 1; i <= length; i++){
            int index=random.nextInt(chs.length);
            code+=chs[index];
        }
        return code;















    /*public static String generateVeriCode(int len){//1
        String code="";//1
        char[]chs={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
                'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',
                '0','1','2','3','4','5','6','7','8','9'};
        Random rand=new Random();
        for(int i=1;i<=len;i++) {//len次
           // int index = (int) (Math.random() * chs.length);//随机下标（0到61的随机数）
            int index=rand.nextInt(chs.length);//随机下标（0到61）上面太啰嗦，这种应用率更高
            code += chs[index];//获取随机字符并拼接到code中
        }
        /*
        i=1 index=0 code="a"
        i=2 index=61 code="a9"
        i=3 index=25  code="a9z"
        i=4 index=28  code="a9zC"
        i=5 index=

            return code;//1

     */
    }
}